The sounds produced by the earliest personal computers were limited to occasional beeps and clicks through the speaker inside the case. There were programs that could make high beeps and low beeps, and some really goofy programs that made the computer talk like one of those robots in a bad science fiction movie, but the sounds produced by those computers were really just audible signals.
It didn't take long for sound cards to appear as plug-in expansion cards that could play recorded sounds in games, educational programs, and other software. These sound cards used external speakers that sounded a lot better than the little ones built into the case, so music and speech could actually sound like something produced by human beings (or in many games, by aliens from outer space).
This was all happening at about the same time that digital recordings on compact discs were beginning to replace the older analog vinyl records and cassette tapes. As these two trends (computer sound and digital audio) evolved, it was inevitable that personal computers would make more extensive use of sound. Today, millions of people use their computers to store and play music and other recorded sound.
Sound cards aren't limited to playing recordings that were created someplace else. The same cards also have input circuits that can record and store sound from microphones and other sources. As the performance of computer-based sound has improved, most radio stations and recording studios have replaced their old tape recorders with high-quality sound processors connected to computers.
A sound card, or a sound controller built into the motherboard, is now standard equipment on most new personal computers, and Windows uses a long list of prerecorded sounds. Audio has become an essential part of the overall computing experience.